Machzor (מִחזוֹר, i.e. cycle) is the title of that part of Jewish liturgy which contains generally the prayers used in the synagogues on the Sabbath and feast- days, but principally those of the three most important festivals. They are usually rythmical, and are the productions of the most eminent Jewish writers. Unfortunately, many of the modern Jews cannot understand them in the original, and are obliged to have recourse to translations. The first author of such a collection of Sabbath and feast-day prayers, Piutim (פיוטּים), is R. Eleazar ben-Jacob Kalir, usually known only as Kallr (קליר), who lived in the second half of the 10th century. This was followed by others (Peitanim, ייטנים, ποιηται). The time of the Peitanim really closes with the 12th century, although fragmentary works still appeared in the 13th and 14th centuries. These collections vary generally according to the nationality of the author, as divers rites and liturgies obtained in the synagogues of different countries. Thus there are Machzors according to the rites of the German, Polish, Spanish, and Italian Jews, and also translations from the Hebrew into the different languages, the use of which translations in the synagogues is, however, not general. The first scientific work on the Machzor is that of W. Heidenheim, published in 1800. This author corrected the text by means of ancient MSS., according to the German and Polish rites, and added to it a commentary and a historical introduction. His work gave rise also to further researches on the Peitanim and liturgies by other modern Jewish writers. Among them may be mentioned Rapoport (Biographie Kalirs, etc., in Bikkure Haïttim, Vienna, 1829-32), Zunz (Gottesdienstl. Vorträge d. Juden, p. 380395), S. D. Luzzatto (כמנהג בני רומא טביא למהזור Einleit. z. Micachsor nach röm. Ritus, Livorno, 1856), and L. Landshuth (עמודי חעבודה, Onomasticon auctorum hymnorum Hebraeorum eorumque carminum, fasciculus 1, Berol. 1857). There is a beautiful edition of the Machzor, and a masterly version of it in German by the late Dr. Sachs, of Berlin. See Bartolocci, Biblioth, Magna Rabbin. 1:672; 4:307 sq., 322 sq.; Wolf, Biblioth. Hebr. 2:1334-49; 3:1200 sq.; 4:1049 sq. SEE LITURGY.